package j04zuoye;

abstract class C1{
    abstract void f1();
}
class A extends C1{
    void f1(){
        //1
    }
}

class B extends A{
    void f1(){
        //2
    }
}

public class J0weichen {
    public static void main(String[] args) {
        new B().f1();
        new A().f1();
    }
}
